The infant was taken from his home just four days after he was born. His mother told police a heavyset white woman arrived at her home posing as an immigration agent.

At a Wednesday news conference, Gurrolla said she had never seen the woman, who threatened to arrest her, then got a knife from the home and stabbed her several times.

Silas took the victim's cell phone, which helped investigators locate Silas, said Joel Siskovic, an FBI agent in Memphis.

Cathy Nahirny, a senior analyst for infant abduction cases at the National Center for Missing & Exploited Children, said there have been at least two other recent cases where an abductor used a ploy similar to the one used in this case.

"We need to get the word out to our immigrant communities," Nahirny said. "Anybody that claims they are from federal law enforcement agencies, you have the right and you should ask for photo identification."